Multi-torsion-meter



'July 9, 1935.

L. P. SMITH MULTLTORSION-METER Filed April 23, 19 5 Sheets-Sheet 1 ATTORNEY July 9, 1935. 1 $M|TH 2,007,220

MULTI-TORSION-METER Filed April 23, .1952 5 s t -sh et 2 INVENTOR L YBRfl/YDPSM/TH. F1 [TL 1 ATTORNEY y 1935. P. SMITH 2,007,220

I MULTI-IICRSION-METER Filed April 23, 1932 5 Sheets-Sheet 3 03 F1 Er. 10.

M W Cm maM ATTORNEY July 9, 1935.

L. P. SMITH MULTI-TORSION-METER Filed April 23, 1932 5 Sheets-Sheet 4 INVENTOR .LVBPHNDPSM/TH BY ATTORNEY July 9, 1935. p $M|TH 2,007,220

MULTI -TORS ION METER Filed April-23, 1932 5 Sheets-Sheet 5 lgl Maw

ATTORNEY Patented July 9, 1935 u i Eo STATE-S PATENT OFFICE (Granted under the act of March a, lass, as amended April 30, 1928; 370 0. G. 757).

This invention relates to a system for observing the stress phenomena in a power shaft rotating under load.

'The object of my invention is to. provide means to measure the torsion of such shaft as an entirety, to study the torsion at any one of a. desired number of phases during a singlerevolution if ..the torque is not uniform, to observe the phenomenal present between such phases, to measure the average torque, andto count the revolutions of the shaft during a definite time interval.

With the above and other objects in view, this invention consists in 'the construction, combination and arrangement of parts as will be described more fully hereinafter. a

In the drawings:

Fig. 1 is a schematic diagram of a system em bodying my invention where are shown installa- 20 tions of indicating instruments at three different locations, at two-wire circuit being indicated by a line made up of dashes anda three-wire circuit by a line made up of dots and dashes in groupsof two;

Fig. 2 is a top plan view of an optical system that forms a part of my invention;

Fig. 3 is a side elevation of the parts shown in i 2;

Fig. 4 shows a form of torsion tachometer that may be used in my invention;

Fig. 5 represents the power end. of the 'shaft to be studied;

Fig.'6 shows the angular relation between the p..rt of the shaft shown in Fig. 5 and a shutter. driven thereby when lag is present in the connections;

Fig. 7 represents the driven end of the shaft with the angle of torsion under load indicated thereonj Fig. 8 represents the relation between a mirror driven from the part shown in Fig. 7

Figs. 9 and 10 illustrate other forms of torsion tachometers;

45 Fig. 11 illustrates one form of torque analyzing device; 7

Figs. 12 and 14 show a disk shutter used in the torque analyzing device;

Fig. 13 represents diagrammatically the rota- 50 'tion of the main shaft as divided into a plurality of phases;

Fig. 15 is a view of another form of torque 55 analyzer;

- to be measured. The light beam is reflected by Fig. 18 is a side elevation of a simple torque averager;

Fig. 19 shows diagrammatically the relation of the parts of a mechanism for exploring the rota .tion of the main shaft by stepless gradations; 5

Figs. 20 and 21 are details of the torque averaging device employed in my invention. 1

Referring more particularly to Figs. 2 and 3 of the drawings, 25 indicates a source of light pro-' jecting a. brilliant beam of parallel rays by means of any suitable optical system. The light beam is interrupted by a revolving shutter 26 provided with pairs of diametrically opposed slits 21 that permit a momentary flash of light to pass through the shutter to a revolving mirror 28' mounted .upon a suitable support 29. The shutter shown in the drawings is a barrel type shutter chosen on account of the sharp occulting effect produced, but it is to be understood that other types may be used without materially lessening the efficiency of the instrument. It will also be understood that any number of pairs of slits may be provided, it depending-on the number of flashes desired per revolution of the shutter. The V shutter ismounted on a; rotatable shaft 30 that '25 passes through support 29 and the revolving mirror is secured to a rotatable shaft 3|, the two shafts being suitably and similarly driven by opposite ends of a main shaft 32 whose torsion is the mirror to a scale 33, preferably translucent, that may be calibrated in any arbitrary marks, as for example in degrees of twist, or to read directly in foot-pounds of torque for the shaft. If desired, a moving strip of sensitized film may be used as indicated at 34, Fig. 1, instead of the scale shown in the Figs. 2 and 3 and a. record kept not only of how the torque may vary with changes of operation, but also of how the torque may vary at a. number of different phases in any one revolution of the main shaft. The source of light, shutter and mirror are housed in a light-tight casing 35, as may be seen more clearly in Fig. 1.

Figs. 5, 6, land 8 show an application of the problem to be solved, wherein: 45

P represents a cross section of the powcr end of the shaft;

D represents a cross section of the driven end of the shaft;

S represents the shutter; and M represents the mirror. S is driven by P, and M by D, so that they will revolve at some given ratio (m) say six revolutions of S and M to one revolution of P and D.

With everything at rest, the top of P and D is 1 zero degrees. The shutter and mirror can be adjusted so that the slits in the former will be in alignment with the source of ,light. Then the mirror will reflect a beam of light on the scale at the zero mark. When. the main shaft 32,

1, starts to revolve without delivering power,

' ror, the shutter will deliver two flashes of light per revolution of itself, and the mirronwill reflect one of theseflashes.per revolution of itself and the shutter. Each flash will bereflected at the zero mark on the scale with only a slighthalo due to the motion of the-mirror during the extremely short time of duration of the flash.

Some lost motion or slip will occur, however, with any set of mechanical, electrical, or electro-mechanical driving connections for the shutter and mirror'that it is mechanically practicable to make. However, two sets of such driving con-- nections may be provided that will not only have small amountsof slip, but also the slips will be so nearly identical that the, lost motion or slip in the one set is substantially equal to that'in the other. J i Q Due to this lost motion or slip, when the main shaft 32 is revolving, the shutter'and mirror will lag behind P and D by very small angles. These angles will be identified and mm espectively,-

and since it is possible to make them very nearly equal, let :r :|:m='a: for the purpose of the followin n lysis.

When Band D are passing the.zero point, S andMwillbelaggingzP,orwillbeatz "(shown ditically by the dotted arrows ,in Figs. 6-and 8).

When P and D are passing +29, Stand M will be at the zero point, and-will throw the light beam to zero on the scale. This is due to the shaft 32 not delivering power, i. e., is not being twisted by home; d I

When the main shaft -32 is delivering power, torque will be set up and D will lag behind I? by some angle of twist, designated as T (Fig. 7) Therefore: a

WhenPisatO,Dwillbeat-T; Swillbeatx; Mwillbeat :c mT

(where m isthe multiplying ratio of the drive gearing) WhenPisatplusv,Dwillbeatplus 3 T; S will be at 0; Mwlll be at 0mT The light beam will be cast through the slits in 7 through the the shutter, strike the mirror, be reflected scale. a

In the case given, with m=6, suppose T is 3:

The light is then reflected 7 through 2mT= The type of driving-connections between the power end of the main shaft and the shutter and the delivery end of the shaft and the, mirror is 'not a part of the present invention. It must Should one driving connectioncontain a certain ..number of .gears, universal joints, belts, chains,

lengths of flexible shafting, self-synchronous generators andmotors, the other driving connection should be.made up, of a like number, even though the structure ofthe surrounding angle 2mT,'andbe indicated on the I engineering plant would not require such a number merely to transmit motion without regard to the amount of lost motion or slip.

I have found one of the most suitable types of driving connections to be a self-synchronous electrical system of transmission of angular positions. Such a system is diagrammatically shown in Fig. 1 wherein 36 designates generators or transmitters of that type adapted to be driven through shaft 31 and intermediate gearing 38 from the main shaft 32, and 40 and 4| are 00- operating synchronized motors or receivers connected with the generators through the electric circuits shown, the dot and dash line being three phase, and the dash line two phase. The motors 40 and 4| drive ,the shutter 26 and mirror 28, respectively. A separate generator or transmitter 42, driven through intermediate gearing 43 from the gearing -38, drives receivers or motors to operate analyzing shutters to be described.

45 represents a connection to any suitable ex-f terior source of electric power.

Fig. 11 illustrates an attachment for the torsion meter above described. It is a torque analyzer in the form of an analyzing shutter 46 that may be installed to select flashes resulting from any particiilar phase of the revolution of the main shaft. Therefore, the torque at each phase may be'studied separately enabling an analysis to be made, which is especially valuable in cases of non-uniform iprque or of torsional vibration.

The analyzing shutter may be placed between the source of light 25 and the revolving mirror 28, on either side of the shutter. It has an opening 41 adjacent to its periphery to permit the passage of light beams once per revolution of the main shaft whose torque is being measured. The shutter is loosely mounted on shaft 48 which revolves at the same rate of .speed as the main shaft, and is driven through reducing bevel gears 49 and 50 from the same shaft 30 .that drives the shutter 26. The analyzing shutter is driven by a boss 5| that is carried 'by a collar 52 fixed to the shaft .48 and flts through any one of a holding nut54.

Although the example given in connection.

with the torsion meter was for an apparatus giving six flashes per revolution of the main shaft,

been used, but for the sake of clearness the following discussion will be confined to the basis ,of six flashes.

On this basis the opening in'the analyzing shutter might have been theoretically one-sixth of 360, or 60. To allow for errors-of construction and the like, reduce this opening to some any convenient number (11) of flashes may have great accuracy of workmanship is required to have the opening 41 match up with the slit in shutter 26 This is an advantage since it eliminates all effects of lost motion in the driving apparatus which actuates the analyzing shutter '46.

-The;principle involved in the operation of the torque analyzer may beunderstood from Figs. 13 and 14. In Fig. 13 each rotation of theshaft has been divided into six phases represented by the dots -4, 55-2, etc.,' on the circle. When the disk 46 is mounted with the aperture 53 that is radially inwardly of the opening 41 engaged-- with theboss 5|, then the opening 41 willalways be in position to permit the passage of a. flash of light to the mirror 28 din'ing the phase 55l of .the rotation. If the aperture 53 next in advance in the, clockwise direction from the open- -ing 41 is engaged with boss 5|, the flash will occur during phase 55-6, etc. It is to be understood that the rotation of the shaft may' be divided intoany number of phases corresponding'to different parts of the cycle of a reciprocating en-' gine, for example. The direction of rotation ofthe main shaft 32 is immaterial, as my invention may be operated in either direction; when it is not desired to use the analyzing disk, it may be removed from shaft 48, or merely heldinthe operative to the inoperative condition while the system is in operation. I havetherefore provided the alternative form disclosed in Fig. 15 to permit such changes to be. made without stopping the apparatus. The analyzing disk 46 is mounted upon a hub 56 that has an inwardly extending lug 51. Hub 56 is mounted on a drum 58 that has a groove 59 adjacent one end thereof and opening into the groove aogellical groove I59. that makes one revolution ar d drum 58. A .slot 60 opens into groove 58 to permit the passage of lugs 51 when mounting the hub 56 on drum 58. A forked shift lever 6| .is slidably mounted on a rod 62-and has a contact roller 63 at the" end of each prong. Alatch 64 is m unted om shift lever 6| tdengage a slot in di k 46 whereby the disk 46 may be held stationary with its aperture 4'! disposed to permit the passage-of light from the lamb 25 to mirror 28. Lateral movement .of lever" Bl will cause the disk 46 tobe moved inthe same direction through contact of rollers 63 thereagainst, andthe-lug 51 will enter the' helical groove 59;, mg 51- will have driving engagement with the wall ofgroove I59 and disk 46' will be caused to rotate'with drum 58. i It is apparent that the position of disk 46 with respect to groove I58 will determineat what part of a rotation the opening 41 will permit passage of light through disk 46. T0 fix the position of disk 46 for analyzing any desired phase of arota tion, a bar 65 is'placed adjacent rod 62 and is provided with clips adapted to receive handle 66 of lever 6|, these clips being so positioned that when handle 66 is engaged by one of them, the

. disk 46 will; be adapted to analyzea phase of v the rotationj Shaft 61 would in this embodiment be connected in place of shaft 48 in Fig. 11.

Instead of using the purely 'mechanical torque analyzers shown in Figs. 1l and 15, an electro mechanical device such as that shown in Fig, 17 may be employed for this purpose. 'In this figure the bearing frame 68may have mounted therein a stator 69 within which a rotor I8 is mounted. The rotor .10 is connected tothe generator 42 andis self-synchronous therewith, while the 5 stator 69 has in it a synchronized-rotating field,

the. disk 46 being mounted on the rotor shaft; 7

. 'Assume the arrow on stator 68 to-be set opposite the arrow 1 on stator frame 68; then the radial arrow on the rotor HI will point to the arrow on the stator at each occurrence of the first phaser 3 to the arrow 2 on the stator frame, then the light will be passed. to the mirror at the occurrence of the. second phase, etc. Stator 68-is fixed in any i setting by means of a set screw 1|. When it is desired to keep the disk 46 inoperative, the arrows In some instances it is desirable'gto ascertain the stress conditions in shaft 32 betweenthe.

phases of the rotation. In the case of a well balanced turbine this would not be necessary but might be of considerable importance where shaft 32 is driven by a reciprocating engine or an internal combustion engine, both of which deliver a non-uniform torque. The? generator used for this purpose is disclosed in Fig. 19 L Since identical mechanism is used in connection with both the mirror 28 and the shutter 26, but one of them will be described. The stator I4 is not permanently fixed but is free to be rotated and then locked at any desired position in the bearing frame 15.. The rotor 13 is drfven by shaft 32 to revolve at some multiple of the speed of the main shaft; inthe case shown this multiple is 6. The radial arrow on the rotor corresponds to the pdsition of'one of its poles and opposite this pole,there will be generated a -pole in the revolving field of the stator. Stator I4 is so connected to the synchronized motor 16 on the shaft of shutter 26 that, as the generated pole of the light will pass to mirror 28. Bearing frame 15 is calibrated in- 5 degree divisions. If the arrow on stator 14 be turned tothe first division, the flash will pass to mirror 28 at 5 degrees from'the first phase, if atthe second mark, at 1.0 degrees past theflrst phase, andso on. In this way, the entire rotation may be explored by stepless gradations and the stress conditions be determined accurately at any desired point in the rotation of shaft 32. It is to be understood that the generrevolving field-passes the. arrow on the stator, the

ator driving the shutter as just described mustbeset the same as the onefon the other end of-lthe shaft 32 which drives theco-acting mirror.

The electric leads. feeding the stator and rotor are not shown in the schematic drawings. There should be enough slack in them to allow moving the stator 180 either way from its midpoint, thus relative position in the bearing frame. This mechanism may be installed on either a. generator or amotor, the latter being used in the installation shown in Fig. 1.

It may be desirable to. obtain a measure of the 50. making it possible to set the stator in any desired in'which a shaft 1'! drives a shaft 18 through spring 19 there being a fly-wheel mounted on a The fly-wheel 86 .will tend to keep the shafts rotating at a uniform rate while thespring IS-permits minor variations in the rate of rotation of shaft". Figs. '20.and 21 give the details of one form of torque averaging means that may be employed in my invention. Shaft 8| may be either shaft 30,of'shutter 26 or shaft 3| of mirror 28. A clutch cone 82 is secured to the lower end of shaft 8| "in a conical recess centrally dis in a fly-wheel as. A forked arm 34,15 pivotedjat '85 and carries-a roller 86 at the outer extremity the bottom of an annular groove 81 in the lower f face of fly-wheel as to lift the fly-wheel out of driving engagement with cone 82 when" desired. Handle 88 of the lever 84 may be disposed under a pin 88 on a locking sector 80 to retain fly-wheel 83 in the disengaging position.

It is obvious that the fly-wheel 83 must be disengaged when the apparatus is being used to observe the phases of rotation of the shaft since the purpose of the fly-wheel when engaged with cone 82 is to produce uniform rotation of shaft 8|. The member 8| serves both as a hearing or guide for shaft 8| and as a. stop to prevent undue upward movement'of fly-wheel 83. It is important that the fly-wheel be so connected to shaft .8I that there will be no lost motion between the fly-wheel and cone 82 during either acceleration or deceleration and further that the fly-wheel shall be so balanced that it will not have a natural period of vibration that will put the system in resonance with the.'non-uniform torque of the main shaft. As shown in Fig. 1, there is a flywheel 83 mounted to be connected to the shaft of shutter 26 and one for the shaft of mirror 28. The lever 84 and rollers 86 make provision for engaging fly-wheel 83 with, or disengaging it from, cone 82 while the shaft BI is rotating at high speed. I a

The ,usefulness of my invention is extended by the torsion tachometer now to be described. It has a number of advantageous features in that it does not depend upon gravity, centrifugal force, stroboscopic effects or clock mechanism. It can analyze the speed of shaft 32 at any phase of a single revolution or can be used when. the torque is averaged by the mechanism aboveset forth. Several embodiments of my'tachometer are shown in Figs. 4, 9 and 10. In all the forms shown in the enumerated figures, the shaft 82 is driven by a synchronized motorJG and is provided with a torque averaging cone 82 and flywheel 83. Depending from shaft 82 is a torsion wire 88 to which is secured a mirror 84. A metal disk 85, which may be of aluminum, is carried by wire 88 and is retained in position by a pin 85 connected to disk 85 that is rotatable in a guide I 81. Light from a source'25 passes through a slit 88 in a screen I that is disposed in front of slit IOI in a cylindrical shutter I02 (Fig. 10)

mounted on shaft 82 to prevent light from slit 88'reacliing mirror 84 except when slit IIII is aligned with slit 88. A scale 108 is disposed to receive the flashesof light from: mirror 84. Disk 85 rotates between the poles on the magnet I04 and therefore, when the disk is in rotation, eddy currents are set up in the disk which exert a braking effect on wire 88 and twist the wire proportionately to the speed of rotation of disk 85.

With all parts of the mechanism at rest, the apparatus can be so set that the slits 88 and IM are aligned, and the beam of light reflected from mirror 84 will strike the zero point on scale I 08.

If shaft 82 is then set in rotation, the braking effectbetween'disk 85 and magnet I04 will twist "wire as a definite amount that is proportional to the speed of rotation ofshaft 82, and the .re

flected beam from mirror 84 will displaced displacement will also be proportional to the speed of rotation of shaft 82. It is apparent that scale I08 may be'so calibrated that it will indicate directly the number of revolutions per minute of, shaft 82 which maybe driven by motor I8 either at the a ship, that designated by B may be in the log 30 that is adapted to be aligned with a slit III in a 5 screen I08 interposed between disk I85 and light source 25. This form of shutter requires a mirror I08 to reflect the light from source 25 to mirror 84. Fig. 9 shows still another embodiment wherein a barrel shutter] I0 provided with diametrically op- 10 posite slits I I I is rotated between light source.

25 and mirror II2 which reflects to the mirror I08 the light that comes through the slits III when both are aligned with light source25.

Disks 3 in Fig. 1 are driven by motors I5 to speed of shaft 32. When the parts of motor I8 are set as described in connection with Fig. 19, the flashes of light from source to mirrors I08 and 84 and thence to scale'33 can be made to occur at any point in a single revolution of shaft 32 and thereby the instantaneous speed 'of rota- 25 tion of shaft 32 can be measured step by step.

Fig. 1 shows schematically a complete installation involving my invention. The assembly designated generally by A may be on the bridge of room, and that designated by C in the main control room. On the bridge are shown a simple torsion meter including the shutter 28 and mirror 28 driven respectively from two separated points on main shaft 82 at six times the speed of the shaft, and a tachometer to measure the time rate of the shaft revolutions. The form of tachometer here shown is somewhat different from those previously described in that mirror H4 is suspended on a wire II5 that is fixed at its upper. 40

source 25 passes through a slit in screen I2l to mirror II4. As magnets II1 rotate, they drag disk I I5 around with them until the torsional resistance of wire II5 .equals the tractive force of the magnets on disk 8, which results in a deflnite displacement of the beam of light from mir- H4 to scale I82 proportional to the rotsif ti nal speed of magnets III.

In the log room are the light source 25, the shutter 28 and mirror 28 arranged as before described, the light from the mirror :0 being projected upon a moving sensitized strip 84 driven by. a motor I 22. The film is enclosed in a light-tight compartment I28. A source of light I24 may be illuminated temporarily by means of switch I25 to project a beam of light on sensitized strip 84 use in analyzing the torque as previously described. Motors 15 that-drive the shutter and the mirror are provided with the torque averaging fly-wheels 88'. There is also a'tachometer to make possible the measm'ing of the time rate of shaft revolutions in the log room.- 'Iheinotors I8 areconstructed to permit ottheir use as phase divider apparatusv described in connection with Fig. 19. V

Theequipment in the main control roo'mls the same as that in them: that the It is obvious that by operating th shutter andthe mirror of the torsion meter at 'six times the rate of rotation of the shaft,'any twist in the shaft between the respective points of connection of the shutter and mirror thereto will be multiplied by six and therefore much more accurate reading is possible. Further, the system herein shown makes it possible to install the apparatus at places distant from the shaft where it is most convenient in respect to space and accessibility. Further, it is obvious that the two points of connection to the main shaft may be as far apart as desired without regard to intervening couplings, or bulkheads, thus increasing the absolute amount of twist available for measurement and consequently enhancing the accuracy of'measurement. I v Y It will-be understood that the above description and accompanying drawings comprehend only the, general and preferred embodiment of my invention, and that various changes in construction, proportion and arrangement of parts may be made within the scope of the appended 1-. In means for observing the phenomena of a.

rotating shaft, a source of light, a rotatable mirror disposed to receive light from said source, a shutter comprising a rotatabiy mounted cylindrical member with diametrically opposed slots interposed between said source and said mirror, means to drive said mirror from a point on said shaft,

other means to drive said shutter from a point on said shaft distant from the aforesaid point, indicating'means disposed to receive light from said n iirror, a clutch cone on the shaft of said shutter andone on the shaft of said mirror, a fiy-wheel engageable with the cone on said shutter shaft and a fly-wheel engageablewith the cone on said mirror shaft, means to move said fly-wheels into engagement withor out of engagement with their respective cones, said mirror and said shutter being driven at a speed different from that of the shaft being ob'served, a slotted disk mounted between said source and said mirror, and

means to rotate said disk at" the same speed as said shaft..

2. In means for observing the torsion phenomena of a'rotating shaft at a plurality of stages in a single rotation, a source of light a mirror rotatable at a speed different from that-of said shaft," disposed to receive light from said source,

I tion to the period of rotation, of said shaft,

a shutter disposed between said source and said mirror adapted to permit the passage of light ;to said mirror at intervals havingxa definite relameans to drive said mirror from a point on said shaft,: other means to drive said shutter from a point on said shaft distant from'the aforesaid point, and indicating means disposed to receive light from said mirror.

3, In means for observing the torsion phenomena of a-rotating shaft, atxa plurality of stages ina single rotation, a source of light;.a rotatable ,5 mirror disposed to receive light from said source,

a. rotatable cylindrical member having diametrically opposed'slots disposed between said mirror and said source, means to drive said mirror from a point on said shaft at a definite rate with respect to the rate of rotation of said shaft but not equal to'the rate of rotation of said shaft, other means to drive said cylindrical member from said shaft at. a point remote" from the aforesaid point at the same rate as. said mirror, and indicating means disposed to receive light from said mirror.

4. In means for observing the phenomena of a rotating shaft, a source of light, a rotatable 'not equal to the rate of rotation of said shaft,

other means to drive saidcylindrical memberfrom said shaft at a. point remote from the aforesaid point at the same rate as said mirror, indicating means disposed to receive light from said mirror,

a rotatable slotted disk mounted between said source and said mirror, said disk being adjustable to different angular positions on its shaft, and

- means to rotate said disk at the same rate as said shaft.

5. In means for observing the phenomena of a rotating shaft, a source of light, a rotatable mirror disposed to receive light from said source, a rotatable shutter disposed between said source and said mirror adapted to permit the passage of I light to said mirror at intervals having a definite relation to the period of rotation oi. said'shaft, means to drive said mirror from a point on said shaft, other means to drive said shutter from a point on said shaft distantfrom the aforesaid point, indicating means disposed. to receive light from said mirror, a fiy-wheel connectible to and disconnectible from said shutter and a second fly-wheel connectible to and disconnectible from said mirror, and means so to connect and 'disconnect said fly-wheels while said mirror and said shutter are rotating.

6. In means for observing the phenomena of. a

rotating shaft, a source of light, a rotatable mirror disposed to receive light from said source, a rotatable shutter disposed between-said source and said mirror adapted to permit' the passage of light to said mirror at intervals having a definite relation to the.period of rotation ofsaid shaft,

-means to drive said mirror from a point on said shaft, other means to drive said shutter from a point on said shaft distant from the aforesaid point, indicating means disposed to receive light from said mirror, a fly-wheel connectible to and disconnectible from said shutter and a second fiy-wheelconnectible to and disconnectible from said mirror, means so to connect and disconnect said fly-wheels while said mirror and said shutter are rotating comprising apivotallymounted bifurcated lever, a roller at the end'of each fork of said lever, and means to lock said lever to hold v said fly-wheels in thedisconnectedposition. V

7. In meansforobserving the phenomena of it rotating shaft, a source of light, a. rotating mirror disposed to receive light from said source, a rotating shutter disposed between said source and .said mirror, means for driving said shutter and said mirror from said shaft, a rotatable apertured disk *disposed between said source and said mirran a rotor operatively connected to said disk, a stator in which said rotor is mounted, said stator being adapted to havein it a revolving electric field and being angularly adjustable about the axis of said rotor, a bearing frame in which said stator is mounted, said stator, rotor and frame each bearing angular position indicia, and electric means driven by said shaft, said means being self-synchronizing with said stator and.

rotor and operatively connected thereto.

8. In means for observing the torsion phenomena of a rotating shaft at a. plurality of stages in a single rotation, a source of light, a movable mirror disposed to receive light from said source, means to intercept the light from said source to said mirrorexcept at predetermined intervals, devices to drive said mirror and said means from different points on said shaft, said mirror and said means being driven at the same speed which is different from that of said shaft, said devices including members adjustable to cause light to pass from said source to said mirror at any desired angular position in the rotation of said shaft, and indicating means disposed to receive the light from said mirror.

9. In a system of the class described, a source of light, a movable mirror disposed to receive light from said source, a shutter disposed between said source and said mirror, separate means to operate said shutter and said mirror, each of said means comprising a rotor, a stator within which said rotor. is mounted, a bearingframe in which said stator is carried, said frame having adjacent said stator calibrations indicating angularr positions, said stator being movable in said frame and bearing a reference mark adapted to be set at any of the said calibra'tion marks on said frame, said rotor havinga reference mark' thereon corresponding in phase position tothe mark on said stator, a'synchronized device to drive said shutter operating means from a point on said shaft, a second like device to drive said mirror from said shaft at a point remote from the aforesaid point, and an indicating device disposed to receive light from saidmirror, all the aforesaid parts being so connected that said shutter will permit light to pass to said mirror from said source at that angular posit on of said shaft indicated by the position of he reference mark, on said stator with respect to the said calibrations on said frame.

10. In a system of the class described, means for measuring the torsional deformation of a shaft including devices driven from said shaft at spaced apart points on said shaft, and means including a movable inertia member associatedwith each of said devices to cause said devices to give a substantially constant average indication during all the phases of a complete rotation of said shaft.

11. In a system of the class described, means for indicating the torsional deformation .of a rotating shaft including devices driven from said ing devices driven from said shaft at points spaced apart on said shaft, and means to prevent thegiving of an indication except at a predetermined instantaneous angular position of said shaft.

13. In a system of the class described, meanr acting togive normally a continuous indication visible from a fixed position for indicating the torsional deformation of a rotating shaft including devices driven at the same speed from said shaft at points spaced apart on said shaft and means to show the angular difference between the rotational phases of such devices, and mechanism to prevent the showing of such difference except at a predetermined phase of the rotation of such shaft.

14. In means for observing the phenomena of a rotating shaft, a source of light, a rotatable mirror disposed to receive light from said source, a shutter comprising a rotatably mounted cylindrical member with diametrically opposed slots interposed between said source and said mirror, means to drive said mirror from a point on said 'shaft, other means to drive said shutter from a point on said shaft distant from the aforesaid point of said shaft, indicating means disposed to receive light from said mirror, a fly-wheel, disengageable means to connect said fly-wheelto said mirror, a. second fly-,wheel, asecond disengageable means to connect said second fly-wheel to said shutter, said mirror and said shutter being driven at a speed diiferent from that of said shaft, a slotted disk mounted between said source ands said mirror, and means to rotate said disk at the same speed as said shaft.

' 15. In means for observing the phenomena of a rotating shaft, a source of light, a rotatable mirror disposed to receive light from said source and a shutter adapted to permit the passage of light to said mirror at intervals having a definite relation to the period of rotation of said shaft, means to drive said mirror from a point on said shaft, other means to drive said shutter from a point on said shaft distant from the aforesaid point, indicating means disposed to receive light from said mirror, a high inertia member connectible to and disconnectible from said shutter and a second like member connectible to and disconnectible from said mirror, and means, so to connect and disconnect said inertia me bers while said mirror and said shutter are rotat 16. Asan article of manufacture, a rotor, a stator on'which said rotor ismounted, said stator being adapted to have in it a revolving electric field and being angularly adjustable about the axis of said rotor, a bearing frame in which said stator is mounted, said stator, rotor and frame bearing angular position indicia, and electric means driven by a rotating element, said means being self-synchronizing with said stator and rotor and operatively connected to said stator and said rotor. 4

1'7. In means for observing. the phenomena of a rotating shaft, a rotor, a stator in which said rotor is mounted, said stator being adapted to have 'in it a revolving electric field and being. angularly adjustable about the axis of said rotor, a bearing frame in which said stator is mounted, said stator, rotor, and frame each bearing angular position indicia, electric means driven by said shaft, said means being self-synchronizing with. said stator and rotor and operatively connected thereto and indicating means operated in part.

by said rotor. a LYBRAND P. SMITH. 

